These are software applications that will help you collect and organize your references and format your papers including your citations (references) according to the style manual you choose. The library is the most equipped to help you with Mendeley. You can learn more about using it on our Mendeley webpage.
Some of these tools you must purchase, but some, like the ones listed below, are available for free.
You should double check any citations you make using these tools though, as they may not be accurate.